Merge pull request #1358 from Xilinx/bugfix/binary_thresholding

[BugFix] Harden thresholding to work for binary case with a single threshold.

Author: auphelia

finn-rtllib/thresholding/hdl/thresholding.sv

@@ -150,31 +150,27 @@ module thresholding #(
 
 		// PE Configuration Address Decoding
 		logic  cfg_sel[PE];
-		logic  cfg_oob;
-		logic [$clog2(N)-1:0]  cfg_ofs;
+		logic  cfg_oob; // Map readbacks from padded rows (non-existent PEs) to padded highest threshold index of first PE
 		if(PE == 1) begin
 			assign	cfg_sel[0] = 1;
 			assign	cfg_oob = 0;
-			assign	cfg_ofs = cfg_a[0+:$clog2(N)];
 		end
 		else begin
 			uwire [$clog2(PE)-1:0]  cfg_pe = cfg_a[$clog2(N)+:$clog2(PE)];
 			always_comb begin
 				foreach(cfg_sel[pe]) begin
 					cfg_sel[pe] = USE_CONFIG && cfg_en && (cfg_pe == pe);
 				end
-				cfg_oob = (cfg_pe >= PE);
-				cfg_ofs = cfg_a[0+:$clog2(N)];
-				if(cfg_oob && !cfg_we) begin
-					// Map readbacks from padded rows (non-existent PEs) to padded highest threshold index of first PE
-					cfg_sel[0] = 1;
-					cfg_ofs = '1;
-				end
+				cfg_oob = (cfg_pe >= PE) && !cfg_we;
+				if(cfg_oob)  cfg_sel[0] = 1;
 			end
 		end
+		uwire [M-1:0]  cfg_ofs;	// Zero-extend for N = 2^k
+		if($clog2(N) < M)  assign  cfg_ofs[M-1] = cfg_oob;
+		if(       N  > 1)  assign  cfg_ofs[0+:$clog2(N)] = cfg_oob? {($clog2(N)){1'b1}} : cfg_a[0+:$clog2(N)];
 
 		uwire ptr_t  iptr;
-		assign	iptr[0+:M] = cfg_ofs;	// Zero-extend Expand for N = 2^k
+		assign	iptr[0+:M] = cfg_ofs;
 		if(CF > 1) begin
 			// Channel Fold Rotation
 			logic [$clog2(CF)-1:0]  CnlCnt = 0;

finn-rtllib/thresholding/sim/thresholding_tb.sv

@@ -47,8 +47,9 @@ module thresholding_tb;
 		bit  deep_pipeline;
 		bit  throttled;	// throttle input and output interfaces occasionally
 	} testcfg_t;
-	localparam int unsigned  TEST_CNT = 3;
+	localparam int unsigned  TEST_CNT = 4;
 	localparam testcfg_t  TESTS[TEST_CNT] = '{
+		testcfg_t'{ k:  5, n: 1, c:  1, pe: 1, sign: 0, fparg: 0, deep_pipeline: 0, throttled: 0 },
 		testcfg_t'{ k: 10, n: 8, c: 12, pe: 3, sign: 1, fparg: 0, deep_pipeline: 1, throttled: 1 },
 		testcfg_t'{ k:  8, n: 3, c:  8, pe: 4, sign: 0, fparg: 0, deep_pipeline: 0, throttled: 1 },
 		testcfg_t'{ k: 17, n: 9, c: 10, pe: 5, sign: 1, fparg: 1, deep_pipeline: 1, throttled: 0 }
@@ -122,14 +123,27 @@ module thresholding_tb;
 			.ordy, .ovld, .odat
 		);
 
+		// Expected Ordering
+		function val_t reord(input val_t  x);
+			automatic val_t  res = x;
+			if(SIGNED) begin
+				if(FPARG && x[K-1])  res[K-2:0] = ~x[K-2:0];
+				res[K-1] = !x[K-1];
+			end
+			return  res;
+		endfunction : reord
+
 		//- Threshold Definition --------
 		typedef val_t  threshs_t[C][N];
 		threshs_t  THRESHS;
 		initial begin
+			static val_t  row[N];
+
 			// Generate thresholds
-			void'(std::randomize(THRESHS));
 			foreach(THRESHS[c]) begin
-				val_t  row[N] = THRESHS[c];
+				static val_t [N-1:0]  r;
+				void'(std::randomize(r));
+				foreach(row[i])  row[i] = r[i];
 				row.sort with (reord(item));
 				THRESHS[c] = row;
 			end
@@ -143,16 +157,6 @@ module thresholding_tb;
 			end
 		end
 
-		// Expected Ordering
-		function val_t reord(input val_t  x);
-			automatic val_t  res = x;
-			if(SIGNED) begin
-				if(FPARG && x[K-1])  res[K-2:0] = ~x[K-2:0];
-				res[K-1] = !x[K-1];
-			end
-			return  res;
-		endfunction : reord
-
 		//- Stimulus Driver -------------
 		input_t  QW[$];  // Input tracing
 		addr_t   QC[$];  // Readback tracking